Researchers test a key element of the theory of gravity in the strongest gravitational field to date—that produced by the supermassive black hole at the center of the Milky Way.
The huge gravitational pull of Sagittarius A*—a black hole behemoth at the center of our Galaxy—makes it an ideal object to verify the validity of theories of gravity, including the general theory of relativity (GR). But to date, researchers have confined their gravity checks to less massive astronomical objects, such as the Sun or white dwarfs. Now the GRAVITY Collaboration has performed a black hole test, using the light emitted from a star orbiting Sagittarius A*.